The present invention relates generally to the concept of dimensional weighing to determine the charge required by a carrier for transporting a package or parcel, and more particularly to a dimensional weighing system suitable for use by a variety of shippers and carriers to determine accurate freight charges for packages or parcels that are considerably oversized in comparison to their actual weight.
The concept of dimensional weighing has long been well known, and prior art relating to various dimensional weighing systems and apparatus has been available for over forty years. However, the concept of dimensional weighing did not receive widespread acceptance for many decades due to several reasons. One of these is that when the concept was first developed, the carriers were willing to accept freight charges based on weight as being a reasonably accurate system for determining the charge for shipping individual packages. Since the Government postal system had been determining postage charges for mail delivery based on weight since the inception of the mail system, it was only logical at the time that parcel and package carriers should do likewise. Thus, it became fairly standard in the infant industry to weigh parcels and determine freight charges according to a schedule of charges based on different weight categories. As time progressed and the distances that parcels and packages traveled became greater, a distance factor was added to the formula so that two packages having the same weight would be charged differently depending on the distance that each traveled. However, distance for any given destination from a dispatch location is the same regardless of whether a basic freight charge is based on weight or dimension.
Another reason that delayed the acceptance of the dimensional weighing concept was that at the outset there was no convenient and economic apparatus available for carrying out the dimensional weighing process. The only known method was to physically measure the three dimensions of a parcel that are necessary to determine the volume thereof using a measuring stick or tape. Although this procedure produced the end result desired for the concept of dimensional weighing, it suffered the drawbacks of being slow and tedious, thereby greatly hampering the efficient handling of large quantities of parcels, and it was only as accurate as the person performing the measuring, thereby rendering it susceptible to either over or under charging. As time passed, some forms of apparatus were developed for automatically taking the necessary measurements to determine the volume of packages, but they were generally cumbersome and difficult to operate, and sufficiently expensive that they were not cost effective in terms of the benefit derived from them.
Still another reason for the slow acceptance of the dimensional weighing concept was that packaging techniques commonly utilized in the early days of package and parcel shipping by private carriers were such that they were satisfied that they were obtaining a reasonable and fair return for their service by determining freight charges based on weight. Most merchandise shipped was of a fairly durable nature, and the size of the package was reasonably close to the size of the packaged article, with the result that a freight charge based on weight was reasonably accurate and the concept of dimensional weighing simply wasn't necessary.
As time passed, these circumstances changed; the logic of accepting weight as being the basis for determining freight charges for parcels and packages became questionable since the carriers began to realize that parcels and packages are quite different in many respects from mail, as will become more evident hereinbelow. Further, as interest began to develop in the concept of dimensional weighing, more practical and efficient, as well as less complicated and costly, apparatus began to appear, thereby rendering dimensional weighing easier to perform and with more reliable accuracy. Finally, and certainly not the least significant factor, is that with the development of so-called high-tech materials and methods of manufacture, many products became lighter in weight but more fragile to handle, with the result that packaging techniques changed to accommodate these characteristics. Thus, it became necessary to devise packaging techniques that would protect such fragile products from the obvious hazards of being subjected to rough handling in the course of shipment, with the result that relatively light products were being packaged in relatively large boxes, and the carriers became concerned that they were no longer receiving a reasonable and fair return for their services in the case of a large percentage of parcels and packages being shipped.
The importance of the dimensional weighing concept became evident to carriers with the realization that, with ever increasing frequency, shippers were packing relatively light and relatively fragile products in large cartons and boxes and surrounding the products with various forms of cushioning and shock absorbing materials that occupied considerable space but had little weight. For example, such materials as pre-formed foam panels which conform to the shape of a product so as to cushion it on all sides, foam materials of various irregular shape often referred to as nuggets or "peanuts", which are literally poured into a carton both before and after the product is placed in the carton so as to entirely surround it and insulate it from the sides of the carton, as well as bubble wrap, cardboard or plastic spacers, etc., all became standard package shipping materials. These materials occupy a considerable amount of space and exert virtually no weight. The obvious result of this packaging technique is a relatively large carton having a greatly disproportionate size for its actual weight.
Again, as time progressed, this disparity between the traditional weight-size relationship of the early days of private shipping began to manifest itself in lost revenue to the carriers because of the double effect of being able to transport fewer and fewer parcels and packages in a given shipment due to the increase in the unit size of parcels and packages, combined with the loss of weight which was the primary factor determining the freight charge for a parcel or package. This effect became especially severe with the development of air freight, where two opposing factors can determine whether a particular freight shipment will result in a profit or a loss to the carrier. These factors are the relatively high cost of operating an airplane to transport freight from one location to another, combined with the relatively severe limitation on the amount of space available for carrying the freight on each plane. Thus, if one plane carrying a certain volume of freight is transporting relatively heavy products on which a substantial freight payment was charged by the carrier, the operation will be profitable. If, on the other hand, the same plane carries the same volume of freight, but the products are relatively light in weight while the cartons are large due to the quantity of shock insulating material in the carton, the freight payment charged by the carrier based on the weight will be considerably less than in the first example, with the result that the profit to the carrier will be much less, if not entirely absent.
Thus, within the last ten years or so, the carriers have come to realize that the traditional basis of weight for determining freight charges is no longer acceptable in the case of a large percentage of parcels and packages, and they have at least partially if not fully embraced the concept of dimensional weighing. And the carriers have sought to enforce shippers, both large and small, to do likewise with considerable success, with the result that the need for highly efficient, accurate and inexpensive dimensional weighing equipment is steadily increasing. As the carriers turned more and more to dimensional weighing techniques to determine freight charges for what appeared just prior to shipping to be very light packages for their size, the carriers would dimensionally weigh such packages and would assess the freight charge based on the dimension of the package rather than its actual weight, and this charge would be billed back to the shipper, who would then incur a loss of the difference between what the shipper had invoiced the receiver for the freight charge and what he was billed by the carrier based on dimensional weight. For example, if a shipper, e.g., a manufacturer, engages a carrier to transport a certain number of large cartons to various receivers, e.g., wholesale distributors, with each carton containing a certain number of relatively light, fragile products, and the shipper has invoiced each receiver for the price of the goods plus a freight charge based on the weight of each carton, the shipper receives the invoice immediately after he ships the goods. When the carrier takes possession of the cartons, he sees that they are relatively light for their size and he dimensionally weighs each carton, and thereby determines a freight charge substantially larger than that which the shipper determined based on weight and for which he invoiced the receiver. The carrier now bills the shipper for the freight charge based on dimension, but the shipper has lost his best opportunity to recoup this larger charge from the receiver, since he has already invoiced the receiver for the lesser freight charge. The shipper thus lost money on the transaction by underestimating the proper freight charge for that shipment by having initially determined the freight charge based on weight rather than dimension.
As the practice of dimensional weighing became more commonplace, certain guide lines were developed to assist in making on the spot determinations of which packages and parcels should be dimensionally weighed and which should not, since it is neither necessary nor efficient to dimensionally weigh every parcel and package that passes through either the shipper's or the carrier's hands. Thus, it has become rather well settled that any parcel or package that has a volume in excess of a minimum size, e.g., one cubic foot, should be dimensionally weighed, unless it is obvious to the weigher that it is sufficiently heavy that a freight charge based on weight would be reasonably accurate. The typical individual length, width and height dimensions used to determine the one cubit foot volume are 12".times.12".times.12", but other dimensions could also result in a one cubic foot volume. Also, the minimum volume may vary from one cubic foot depending on the practice of individual shippers and carriers.
Although the concept of dimensional weighing has now been generally accepted and the practice has become relatively commonplace, there still remains a shortage of suitable apparatus for carrying out the practice. There are certain characteristics which dimensional weighing apparatus must possess in order to be considered suitable for performing dimensional weighing in the most practical and cost effective manner. Firstly, the apparatus must be sufficiently non-complex that it can be operated by persons without specialized technical training. Secondly, it must have the capability of operating with considerable speed in order to handle a large number of parcels in rapid succession. Thirdly, it must have a high degree of accuracy consistent with the extent of resolution that is desired in a particular installation. Fourthly, it must be easy to install and maintain, and have a high degree of reliability for long term consistent operation. Finally, it must be sufficiently economical that it is more cost effective for a shipper to purchase the apparatus than to continue running the risk of consistent undercharging for packages that are inordinately large in comparison to their weight.
Until the advent of the present invention, there was no single piece of dimensional weighing apparatus that possessed all of these characteristics. Prior art dimensional weighing apparatus has consistently suffered from having one or more of the disadvantages of being bulky and difficult to operate, slow in operation and subject to various extraneous conditions that adversely affect the accuracy, and expensive in compared to the benefits derived and therefore not especially cost effective. Certain older forms of dimensional weighing apparatus relied on mechanical switching arrangements contacted by a carton placed on a scale platform, thereby adversely affecting the accuracy of the scale and also introducing a considerable degree of unreliability of the mechanical parts for proper and consistent operation. As electronic controls became common, the methods devised for measuring the linear dimensions of cartons and packages were complex and bulky, including ultra-sonic technology which lacked sufficient accuracy and light curtains which could only measure two dimensions of a carton, and difficult for a non-technically trained person to operate. Many of these prior art machines were so expensive that the purchase price could be effectively justified only by the largest shippers, thereby precluding a major segment of potential shippers from practicing dimensional weighing except by archaic manual techniques. Thus, there is a need for dimensional weighing apparatus that possesses the above mentioned desirable characteristics and avoids the shortcomings and disadvantages of the heretofore known dimensional weighing apparatus.